A bag, bottle, syringe, or other container that contains infusion medication or solution is hung from a rack to administer the infusion solution. A tube is connected between the container and an infusion pumping system. A catheter at the end of the tube is inserted into a patient for an intravenous (IV) infusion. The tube may be part of an assembly that includes fittings, connectors, check valves, and pumping elements and is frequently referred to as an “IV set.” The infusion solution is administered to the patient when the infusion pumping system is started.
Existing IV check valves include chambers that include inlet ports disposed on the upstream of the IV check valves and outlet ports disposed on the downstream of the IV check valves. The inlet ports allow the fluid to flow from the tube into the check valves, and the outlet ports allow the fluid to flow out of the check valves into the tube. A post may be disposed in the center of the outlet port opening. The post holds a disk against the seat of the inlet port.
IV check valves are normally closed when there is no movement of fluid (e.g., infusion solution) through the IV set. For example, when there is no movement of fluid, the disk in the chamber sits against the seat of the inlet port so that the check valve is sealed. When the fluid flows through the IV set, IV check valves open and allow the fluid to flow from one end of the IV check valve to the other end. For example, when the fluid flows through the IV set, the flow pressure from the fluid movement deflects the disk and creates a gap between the disk and the seat of the inlet port allowing the fluid to flow through the check valve.
The gap between the disk and the seat of the inlet port may be proportional to the flow rate of the fluid. For example, when the flow rate of the fluid decreases (e.g., a low flow condition), the gap between the disk and the seat of the inlet port decreases. A small gap is susceptible to lodging grit between the disk and the seat of the inlet port. When reverse flow is applied while the grit is lodged, the gap between the disk and the seat of the inlet port does not fully close and creates a small leak which renders the valve to be useless.